The invention relates to check-valves of the variety in which two like valve members are hinged on a single axis, for independent coaction with the respective valve-seat openings defined by a seat post which extends diametrically across the bore of the valve body. Check valves of this character are illustratively described in U.S. Pat. No. 2,877,792 (Tybus), No. 3,538,946 (Hilsheimer), No. 3,678,958 (Satterwhite et al.), and No. 4,079,751 (Partridge et al.).
In the foregoing patents and in all other similar check-valves known to me, the hinge structure for the two valve members extends fully across the diameter of the valve-body opening and requires special machining of the body and/or added parts to be assembled to the bore of the body, for accommodation of the hinge structure.